Unit valve for hydraulic elevator control

ABSTRACT

A unit valve assembly for operation of a hydraulic elevator including three separate valve devices for performing four valve functions, for controlling up bypassing, main down, down leveling and checking are all being made part of a single housing. Controls respectively for up acceleration, up transition, up level, down full speed, down leveling and stop are also mounted on the housing in position, such that adjustments for all said valve devices and controls are located for ready accessability on one side of the housing. A special up level valve having a progressively graduated orifice control is hydraulically actuated to improve the smoothness of up leveling of the elevator.

United States Patent Lawrence et al.

[54] UNIT VALVE FOR HYDRAULIC ELEVATOR CONTROL [72] Inventors: WilliamAnthony Perry Lawrence, Santa Susana; James Arthur Mills, Sunland, bothof Calif.

[73] Assignee: Elevator Equipment Company, Los

Angeles, Calif.

[22] Filed: May 12, 1971 [2]] Appl. No.: 142,639

[52] US. Cl. ..137/596.l6, 60/52 HD, 60/52 US,

91/444 [51] Int. Cl ..Fl6k 11/10 [58] Field of Search....60/52 HD, 52US; 9l/47, 361, 91/444, 468; 137/486, 596.16

[56] References Cited UNITED STATES PATENTS 2,664,9l6 l/1954 Conley..60/52 l-lD X 1 1 Dec. 26, 1972 3,141,386 7/1964 Loughridge ..91 41x3,330,110 7/1967 Sprayberry ..60/52HD Primary Examiner-Henry T.Klinksiek Attorney-Beehler, Arant & Jagger [5 7 ABSTRACT A unit valveassembly for operation of a hydraulic elevator including three separatevalve devices for performing four valve functions, for controlling upbypassing, main down, down leveling and checking are all being made partof a single housing. Controls respectively "for up acceleration, uptransition, up level, down full speed, down leveling and stop are alsomounted on the housing in position, such that adjustments for all saidvalve devices and controls are located for ready accessability on oneside of the housing. A special up level valve having a progressivelygraduated orifice control is hydraulically actuated to improve thesmoothness of up leveling of the elevator.

21 Claims, 8 Drawing Figures HYDRAULIC.

EL. EVA TOR TANK PUMP

(IQ/145$ ,9. Mn. L5

IN VENTORS larroe/vsvs.

PATENTED DEC 2 6 I972 SHEET 2 BF 8 Ros 7K BLm/v Him/0M A 1 lpwes/vcetimes/9. MILLS INVENTORS PATENTED use 26 m2 SHEET 3 BF 8 04 4 00v lV/LL/QM 19... ZQWQEA/CE Jar/145s Q lLLS INVENTORS.

PATENTEB DEC 26 I972 SHEET 5 BF 8 m E \wws m u m 2 4 am OW Rah mINVENTORS PATENTED W22 I912 3.707; 166

SHEET 8 BF 8 R 04 if BL. AWN WLL/QM 19.1 lflW/QENCE JQMESQ MIL 4.9

UNIT VALVE FOR HYDRAULIC ELEVATOR CONTROL Hydraulic elevators arecommonly used for lifts limited in general to a building height nohigher than a feasible and practical length for a hydraulic ram, whichmust be sunk below the surface, a distance approximately equal to theheight of the building. Hydraulic fluid under pressure is suppliedthrough a cylinder in which the ram reciprocates to lift the elevator,gravity being relied upon to lower the elevator. In other words, tohavesuch elevators operate efficiently it is desirable that the ram moveas rapidly as possible throughout most of the distances between floors.To enjoy such rapid movement, however, it becomes desirableto decelerateas the elevator approaches a stop, whether moving upwardly ordownwardly, and to stop precisely at floor level, quickly andaccurately, and with relatively little hunting for the correct level.

Various hydraulic valves have been devised heretofore in an effort toachieve these results. Inasmuch as valves adapted to control the desiredfunctions heretofore made use of have been constructed and assembledindividually, hydraulic circuits for operating them have been somewhatcomplex, difficult to install, troublesome to maintain, and consequentlythe efficiency of such systems has not been as high as desired. Inasmuchas considerable adjustment is needed whenever an installation of suchequipment is made and since appreciable readjustment is necessary fromtime to time, to maintain proper efficiency the making of suchadjustments has presented appreciable problems. Furthermore since theweight of the load on such an elevator varies considerably during normalperiods of use and since the variation in weight produces a veryconsiderable effect upon hydraulic pressuresneeded for operation,considerable adjustment is needed to compensate for such variations.

It is therefore among the objects of the invention to provide a new andimproved unit valve for the control of a hydraulic elevator which is ofsuch construction and configuration that virtually all of the individualvalve devices can be compactly located in a central housing whereby toeliminate many of the troublesome deficiencies heretofore prevalent.

One of the objects of the invention is to provide a new and improvedunit valve for the control of a hydraulic elevator wherein theindividual valve devices are compactly arranged at a single location andin such orientation that virtually all adjustments can be handilymanaged from a single location on the housing.

Still another object of the invention is to provide a new and improvedunit valve construction for the operation of the hydraulic elevator ofsuch construction that a cartridge type relief valve can be used.

Further included among the objects of the invention is to provide a newand improved unit type hydraulic valve wherein three individual valvechambers or cavities capable of handling all of the hydraulic fluidunder pressure are of such construction that they can be located side byside in a single horizontal plane whereby to minimize interconnectionsand to greatly facilitate the operation.

Another object of the invention is to provide a new and improved unittype valve for hydraulic elevator control in which the three requiredvalve devices are compactly arranged whereby to minimize passages andpressure drop, wherein there is a constant mechanical force influencingbleed orifice openings, wherein pressure responsive bleed orificeoperating means is located in the main valve housing and wherein suchpressure responsive devices as are needed for other functions of thesystem are likewise located in the main valve housing.

Further included among the objects of the invention is to provide anorifice control for up leveling which has a variable orifice coefficientwhereby to improve performance and make possible a more preciselyregulated and quieter operation.

Included further among the objects of the invention is to provide a newand improved unit type device for hydraulic elevator control whereinwhen a loaded elevator is descending, a speed sensitive device may beemployed tovary the hydraulic flow thereby to positively and dependablylimit down speed travel of the elevator.

Also included among the objects of the invention is to provide a new andimproved unit type hydraulic control device for hydraulic elevatorswherein a single tool is required for all adjustments and wherein theadjusting means are so located that they can" be effectively sealedbetween service calls.

With these and other objects in view, the invention consists of theconstruction, arrangement, and combination of the various parts of thedevice, whereby the objects contemplated are attained, as hereinafterset forth, pointed out in the appended claims and illustrated in theaccompanying drawings.

In the drawings:

FIG. 1 is a front perspective view of the unit valve housing and showingsundry conventional parts schematically.

FIG. 2 is a diagram of the hydraulic circuit functionable with the unitvalve.

FIG. 3 is a longitudinal sectional view on the line 3 3 of FIG. 1showing valve positions at rest.

FIG. 4 is a fragmentary longitudinal sectional view similar to FIG. 3but showing valve positions occupied during the full speed upwardtravel.

FIG. 5 is a fragmentary longitudinal sectional view similar to FIG. 3but showing valve positions occupied during up leveling.

FIG. 6 is a fragmentary longitudinal sectional view similar to FIG. 3but showing valve positions occupied during downward travel at fullspeed.

FIG. 7 is a fragmentary longitudinal sectional view similar to FIG. 3but showing valve positions occupied during down leveling of theelevator.

FIG. 8 is a longitudinal sectional view of a poppet valve which can beinterconnected with the system for additional control.

In the embodiment of the invention chosen for the purpose ofillustration, there is shown a unit valve construction comprising ahousing indicated generally by the reference character 10 which is setup to operate a hydraulic elevator 11 powered by a cylinder 13 which,operates a ram 12 supplied by a hydraulic line 14. A pump 15 supplieshydraulic liquid through a pressure line 16 to the housing 10 and adischarge line 17 carries hydraulic fluid away to a tank or reservoir18. In the discharge line 74 is located a butterfly type valve 19 whichcan be set to control the effective size of the line.

As readily seen in FIG. 2 a hydraulic circuit interconnects the sundryhydraulic valves which, in actuality, are normally housed within thehousing 10.

As shown in FIG. 3, the housing contains a plurality of chambers,namely, a bypass chamber 20, an up level chamber 21 and a combinationchamber 22. A bypass valve device indicated generally by the referencecharacter 23 includes a bypass valve element 24 which separates saidbypass chamber into a first bypass cavity 25 and a second bypass cavity26. A plug 27 closes the forward end' of the bypass cavity 26. A spring28 seated at one end against a portion of the housing (not shown) isseated in a recess 29 of the bypass valve element 24 and normally urgesthe bypass valve element 24 forwardly into the bypass cavity 26 until aprojection 30 engages an adjusting shaft 31 thereby to fix the openposition of the bypass valve element.

' In the up level chamber 2lis an up level valve device indicatedgenerally by the reference character 32 which includes an up level valveelement 33 adapted to cooperate with an up level valve seat 34; Teeth 3Sserve as a sliding guide for movement of the valve element and provide avariable opening through the valve device, depending on the degree ofits setting.

The up level valve element 33 is located intermediate a first up levelvalve cavity 36 and a second up level valve cavity 37. The pressure line16 from the pump is in communication with the first up level valvecavity 36 and this cavity 36 is adapted to communicate with the firstbypass cavity 25 through a passage 38. Teeth 39 on the bypass valveelement 24 serve as guides and provide a degree of control for the flowbetween the cavities 36 and 25 depending upon the setting of the bypassvalve element 24. A spring 40 acting between the up level valve element33 and a bottom 41 of the second up level valve cavity 37 servesnormally to urge the up level valve element 33 to a closed positionagainst the seat 34. v

In communication also with the up level valve elemeat 33 is an up levelcontrol assembly indicated generally by the reference character 45. Theup control assembly 45 includes'a tubular jacket 46 extending for aportion of its length into the second up level valve cavity 37 and foranother portion of its length into a plug 47 in the forward side of thehousing 10. A neck 48 of the tubular jacket is interiorly threaded, andthe neck moreover extends forwardly of the outermost end of the plug soas to be accessible from the exterior. A spool 49 is carried by the uplevel valve element 33 and extends through the element 33 so that acentral bore 50 in the spool can communicate between the first up levelvalve cavity 36 and a cavity 51 at its forward end. A nut 49' securesthe spool in place. The spool 49 has a reduced portion 52 and adjacentthe forward end the spool 49 is a frusto-conical surface 53 whichprovides a progressively graduated closure for a port 54 formed in anend piece 55 whereby to provide communication between an interiorannular space 56 surrounding the reduced portion 52 and an exteriorannular space 57. An exteriorly threaded head 58 is adapted to engagethe interior threaded portion of the neck 48 whereby to adjust thelocation of the port 54 relative to the frustoconical surface 53. Ahexagonal socket 59 at the forward end of the end piece 55 receptive ofa hexagonal wrench (not shown) is utilized for adjusting purposes. Theadjustment is effective irrespective of the direction of flow throughthe port 54. j

A passage 60 in the plug 47 communicates between the annular space 57and a passage61 in the housing which in turn communicates with thesecond bypass cavity 26. Another passage 62 communicates between anannular recess 63 and a hydraulic control circuit line 64, the annularrecess 63 in turn being in communicattion through a passage 65 with theinterior annular space 56.

In the combination chamber 22 previously referred to is located acombination down level and down main valve indicated generally by thereference character featuring a pilot operated combination valve element7 71 adapted to seat upon an annular combination valve seat 72. Thecombination valve element 71 separates the combination chamber into afirst combination cavity 73 and a secondcombination cavity 74. Guideteeth 78 on the upper side of the combination valve element 71 serveboth to guide the valve element during operation and also to modify flowinto the second combination cavity 74.

A passage 79 serves to provide communication between the second up levelvalve cavity 37 and the hydraulic line 14 as shown in FIG. 6. i

Cooperating with the combination valve is a down level hydraulic controlassembly indicated generally by the reference character 80 consisting inpart of a reciprocating sleeve 81 through which extends a bore 82. Thesleeve is normally urged rearwardly by a spring 83 hearing at one end onthe sleeve, 81 and at the other end against an end piece 84. The endpiece 84 threadedly engages plug 86 so that by adjusting the position ofthe end piece 84 the location of the slot 84' relative to the adjacentend of the sleeve 81 is varied thereby to adjust action of the downlevel hydraulic control assembly. A port 87 in plug 86 is incommunication with an annular recess 88 of the end piece 84 and furthercommunicates with an annular recess 13 8 and hydraulic controlcircuitline 137, in the plug 86.

For manipulation of the various valves comprising the unit valve, thereis provided a hydraulic circuit shown in schematic form in FIG. 2 inwhich are located hydraulic control valves, in addition to the valveassemblies 45 and 80, some of which are hydraulically actuated andothers of which are immediately responsive to solenoid control. As shownschematically in FIG. 2, a down closing and stop valve assemblyindicated generally by the reference character 90 is in communicationthrough a hydraulic line 91 with a main down solenoid 92, and alsothrough a hydraulic line 93 with the first combination cavity 73 of thecombination down level and down main valve device 70. A valve chamber 94is in communication with the hydraulic line 14 through a bore 95 in aplug 96. A slot 94' provides communication between the chamber 94 andthe hydraulic lines 91 and 93.

An up acceleration valve assembly indicated generally by the referencecharacter 97, and which like the down closing and stop valve assembly 90is regularly mounted in the housing 10, is in communication by means ofa hydraulic line 98 with passage 38. An adjacent hydraulic line 99 is incommunication with a relief valve device 100. The hydraulic lines 98 and99 are in communication with the bore 101 in a plug 102, the bore 101having access to a valve chamber 103. The lower end of the bore 101serves as a valve seat upon which a needle valve element 104 is adaptedto seat. A neck 105 in which is a slot 105', is provided with an annularrecess 106 in communication with a hydraulic line 107 and thus incommunication with the second bypass cavity 26, as shown in FIG. 3. Bymeans of a hydraulic line 108 and 109 there is communication withanother portion of the relief valve device 100. Moreover by aninterconnected hydraulic line 110 communication is established with anup dump solenoid 1 12 which controls a normally open up dump solenoidpilot valve 113. By means of a hydraulic line 114 communication isestablished with an up dump valve assembly indicated generally by thereference character 115. A Valve chamber 116 in the up dump valveassembly communicates through a bore 117 in a plug 118 with a hydraulicline 119 leading to a portion of the discharge line 17 and thence to thepump 18. In the up dump valve assembly is a ram 120 slidably mounted ina neck 120, the neck being provided with an annular recess 121,communicating through a slot 116' with the chamber 116.

For down operation there is provided a down control valve assemblyindicated generally by the reference character 122 in which is a chamber123 in the wall of which is a slot 123. The chamber 123 communicatesthrough a bore 124 in a plug 125 with a hydraulic line 126 which leadsto a portion of the discharge line 17. A ram 127 is reciprocatablymounted in a neck 128, the neck being provided with an annular recess129. Through a hydraulic line 130, the annular recess 129 is incommunication first with a normally closed main down pilot valve 131 andthrough a hydraulic line extension 130' with a normally closed downlevel pilot valve 132. The main down solenoid 92 operates the pilotvalve 131 and a down level solenoid 134 operates the pilot 132.

Through a hydraulic line 135 the hydraulic line 130 and its extension130' communicate with a manual lowering valve indicated generally by thereference character 136. In the opposite direction through a hydraulicline 137 communication is established with an annular recess 138 in theplug 86 and in that way with the port 87 in plug 86 and annular recess89 of the end piece 84 of the control assembly 80.

To establish up transition operation of the hydraulic elevator ram andhence the elevator, there is provided an up transition valve assemblyindicated generally by the reference character 140. The up transitionvalve assembly has a chamber 141 in communication through a bore 142 ina plug 143 with a hydraulic line 144 and thus the discharge line 17. Aneck 145 slidably contains a ram 146, and an annular recess 147 in theneck communicates through a slot 141' with the chamber 141 and is incommunication with a normally open up level check valve 148 through ahydraulic line 149. The check valve is subject to control by an up levelsolenoid 150. On the opposite side of the up level pilot valve 148 isthe hydraulic line 64 which, as shown in FIG. 3, is in communicationwith the up level valve assembly 45 through the passage 62 in the plug47.

The relief valve 100 is a substantially conventional spring pressed ballrelief, however incorporating a differential area piston assembly 185slidably mounted so as to reciprocate in a bore 186 in communicationwith passage 38 through hydraulic circuit lines 99 and 98. A ball 187 islocated intermediate a first relief cavity 188 and a second reliefcavity 189 which first relief cavity 188 communicates with the secondbypass cavity 26 through hydraulic circuit lines 109, 108 and 107 andwhich second relief cavity 189 communicates with the discharge line 17through hydraulic circuit line 152. Somewhat similarly the manuallowering valve, in-

. dicated generally by the reference character 136 which includes ram139 with a reduced portion 191 is slidably mounted in a neck 190 withthe reduced portion 191 creating an annular recess 192. The recess 192communicates through port 193 with the hydraulic circuit line 135. Theport 193 being effectively sealed by a conical surface 194 at theterminus of the reduced portion 191 of plug 139, spills into thedischarge line 17 through hydraulic circuit line 153 thereby to send thecar down under'control of the down level valve assembly 80.

The down closing and stop valve assembly previously described is made upof a neck 155 in which is slidable a ram 156, therebeing provided anannular recess 157 in the neck 155 by means of which communication isestablished with the hydraulic lines 91 and 93.

Attention is directed expressly to the fact that, as shown in FIGS. 1, 2and 3 for example, all of the valve devices and valve assemblies havetheir axes in a parallel relationship and all are compactly assembled inthe housing 10. Moreover, except for manual lowering valve 136 andrelief valve 100 all single tool hex key adjustments face forwardly on aforward wall 160 of the housing 10. For ease in making adjustments thosemembers of the sundry valve devices and assemblies which requireoccasional adjustments are provided with hex key sockets, all of thesame size, so that all adjustments can be made by use of a single hexkey wrench from one side of the housing.

For adjusting throw of the bypass valve element 24 a sleeve 161 havinghex key socket 162 is in threaded engagement with the plug 27. In thisfashion by adjusting the sleeve 161 the endwise position of theadjusting shaft 31 can be shifted to a desired position of adjustment.Similarly a sleeve 163 in threaded engagement with the plug 86 isprovided with a hex key socket 164 by means of which the lengthwiseposition of an adjusting shaft 165 can be varied thereby to adjust thethrow of the combination valve element 71 in the combination down leveland down main valve device 70.

A hex key socket 166 in the end piece 84 provides for its adjustment anda hex key socket 59 in the end piece 55, acting in threaded engagementwith the neck 48 provides for adjustment of the position of the port 54with respect to the frusto-conical surface 53 of the spool 49 thereby tovary the effect of the port 54.

Carrying through with the idea of employment of a single hex key for alladjustments, the neck 155 of the down closing and stop valve assembly 90is provided with a hex key socket 168. The neck 105 of the up acand ahex key socket 172 is provided in the neck 120 of the up dump valveassembly 115. The relative location of these various hex key sockets isillustrated in FIG. 1, all being on the forward wall. Only theadjustment for the manual lowering valve 136 and the relief valve 100are located toward the rear, these being on a rear face 173 of a block174 at the top of the housing 10.

OPERATION NON-OPERATIVE POSITION lnthe schematic representation of FIG.2, normal conditions of the solenoids and their respective valves areshown, namely, the main down solenoid 92 and valve 131 is normallyclosed. The down level solenoid 134 and valve 132 is normally closed.The up level solenoid 150 and valve 148 is normally open and the up dumpsolenoid 112 and valve 113 is normally open. Non-operative conditions ofthe three valve devices which actually guide the hydraulic fluid areshown in FIG. 3. The bypass valve element 24 is moved downwardly by itsspring 28 so that the passage 38 is full open. The up level valve device32 is closed and the combination valve element 71 is closed. When thepump is started, hydraulic liquid at full pressure is delivered throughthe pressure line 16 to the first up level valve cavity 36 and thisliquid then passes through the passage 38 into the dump line 17 andthence back to the tank 18. Ram pressure in the system remains static,whatever it may be and other portions of the circuit are vented toatmosphere and therefore at ambient, or atmospheric pressure.

In this setting of valves and valve assemblies as shown in FIG. 3, thefrusto-conical surface 53 is in a position extending over the port 54,thus modifying the capacity of the port 54 to pass hydraulic fluidbetween the passages 60 and 61 and second bypass cavity 26 and theinterior annular space 56, passage 65, passage 62, and the hydraulicline 64 which goes to the up level pilot valve 148 and up transitionvalve assembly 140. FULL SPEED UP 7 When the elevator is to be sent inan upward direction both up solenoids are energized, namely, the uplevel solenoid 150 and the up dump solenoid 112. This changes thecondition of the pilot valve 148 from normally open to closed and thecondition of the pilot valve 113 from normally open to closed. As aconsequence, pressure in the hydraulic lines 108, 110 and 64 will changefrom atmospheric pressure to pump pressure. As a consequence, there willbe pump pressure in the second bypass cavity 26 which will cause thebypass valve element 24 to move upwardly against the tension of itsspring 28 until it closes off passage 38. Pump pressure will then forcethe up level valve element 33 downwardly to open position as shown inFIG. 4 and hydraulic fluid under pump pressure will then pass from thesecond up level valve cavity 37 to the passage 79, around thecombination valve element 71 and into the hydraulic line 14 and thenceto the cylinder 13 and ram 12 to lift the elevator 11. This is thecondition of upward acceleration or full speed up. UP TRANSITION AND UPLEVELING As the elevator approaches some specified floor level the speedneeds to be slowed down before the elevator is finally stopped. Thismeans a transition from full upward speed to a slow upward speed. Toaccomplish this the up level solenoid is de-energized causing it toassume open position for the pilot valve 148 but the up dump solenoid112 remains energized and the up dump pilot valve. 113 remains closed.At a rate according to the relative positions of ram 146 with respect toslot 141 and needle valve element 104 with respect to bore 101, pressurein the second bypass cavity 26 will be modified to less than that inpassage 38, and as pressure in the second bypass cavity 26 tends tolower, bypass valve element 24 will shift, by action of the spring 28,from a position of closing off the passage 38 to a position partiallyopening the passage 38 as shown in FIG. 5. As a consequence, some, butnot all, of the liquid from the pump which is sent into the first uplevel valve cavity 36 travels through the passage 38 and thence into thefirst by-pass cavity 25 from which it passes through the dump line 17.The subsequent modification of pressure in the passage 38 is likewisereflected in the first up level cavity 36, the reduction in pressureresulting in reduction of the force urging the up level valve element 33downward against the pressure of the spring 40. The spring 40 then urgesthe up level valve element 33upward towards its seat 34 carrying with itthe spool 49 with its reduced portion 52 and frustoconical surface 53.At this stage of operation, pressure in the second bypass cavity 26 willtend to be modified by the action of the spool 49 moving thefrusto-conical surface 53 across the port 54 so that further reductionof pressure in the second bypass cavity 26 is restricted to an amountsuch that the bypassvalve element 24 is hydraulically restrained fromfurther opening of the passage 38. Accordingly a balance of forces isestablished with the up level valve element 33 in closer proximity toits seat 34 according to the relative position of the port 54 asestablished by the axial positioning of the end piece 55 by means ofahex key in socket 59. The rest of the fluid flows past the partiallyopened up level valve element 33 thence into the second up level valvecavity 37 and from there through the passage 79 to the hydraulic line 14and hydraulic cylinder 13. Since the flow and pressure is diminished theupward speed of the elevator is slowed as it approaches its stop.Presence of pump pressure in the cavity 51, the effect of which iscommunicated to the forward side of the valve element 33 is acompensating factor, and when in loaded condition, upward travel isspeeded up to a degree. Stalling out under load in the up level phase issubstantially minimized. UP STOP POSITION When the elevator reaches itsdesired level the up dump solenoid 112 which heretofore remainedenergized is de-energized and the up dump pilot valve 113 is thenopened, resuming the position initially occupied in the positiondescribed as non-operative. As a consequence pressure in the hydraulicline 108 is reduced to atmospheric. This means that pressure in thesecond bypass cavity 26 is reduced to atmospheric and the spring 28 willthen become operative to move the bypass valve element 24 downwardly tothe position shown in FIG. 3 in which position all hydraulic fluid fromthe pump is bypassed back to the tank in the path previously described.Since in this position pressure in the second up level valve cavity 37is greater than pressure in the first up level cavity 36, the up levelvalve element 33 will close and trap all of the hydraulic fluid at fluidpressure in the cylinder thereby to hold the ram 12 and the elevator 1 1at its stop.

When the elevator is to be moved from the level just described to astill higher level the procedure heretofore described is merelyrepeated.

DOWN TRAVEL When the elevator is to be moved downwardly to a lower levelboth down solenoids are energized and both up solenoids remainde-energized. This is to say that the main down solenoid 92 and maindown pilot valve 131 are moved from normally closed to open position,and down level solenoid 134 and down level pilot valve 132 are movedfrom normally closed to open position. As a consequence, hydraulic fluidin the line 137 is passed through the down acceleration valve assembly122 where it approaches atmospheric pressure modified slightly. Thisresults in a reduction in pressure in the first combination cavity 73.Ram pressure being greater on the upper side of the combination valveelement 71 as shown in the upper side of FIG. 6, the combination valveelement 71 moves downwardly against the tension of spring 83 andhydraulic fluid from the cylinder 13 traveling through the hydraulicline 14 is diverted into the second combination pocket 74 from which itpasses to the dump line 17 and thence back into the tank 18. In thiscondition of the unit valve, the elevator is moving downwardly at fullspeed.

DOWN LEVEL AND STOP As the elevator begins to approach a selected stopposition during its downward travel it needs to be decelerated graduallyand progressively before coming to a full stop. To accomplish this themain down pilot valve solenoid 92 is deenergized allowing the main downpilot valve 131 to move to closed position. The down level solenoid 134remains energized and the down level pilot valve 132 remains open, butsince the sleeve 81 is in a position such that port 84 is closed off,fluid in the first combination cavity 73 previously at substantiallyatmospheric pressure, modified slightly, now is trapped and pressurefrom the hydraulic line 14 passing through the down closing and stopvalve assembly 90 serves to increase pressure in the first combinationcavity 73 and this pressure assisted by pressure of spring 83 serves tomove the combination valve element 71 upwardly thereby to partiallyclose the opening between the pilot operated combination valve element71 and the combination valve seat 72 until the port 84' is partiallyopened by the action of sleeve 81 moving upwardly upon the insistence ofspring 83, holding the sleeve 81 intimately in contact with combinationvalve element 71. This re-establishes communication between firstcombination cavity 73 and discharge line 17 through the hydrauliccircuit line 137 and the down acceleration valve assembly 122 wherehydraulic fluid from first combination cavity 73 again approachesatmospheric pressure, modified slightly. As a consequence, hydraulicfluid from the cylinder 13 escapes less rapidly and the speed of the ramand elevator is slowed down.

When the elevator reaches a desired level, the down level solenoid isde-energized and the down level pilot valve 132 then moves to closedposition. This prevents any escape of liquid pressure through thehydraulic circuit line 137 and hence pressure in the first combinationcavity 73 builds up with the assistance of spring pressure 83 until thecombination valve element 71 seats upon the valve seat 72 shutting offflow from the cylinder entirely to cause the ram to stop and theelevator to come to its desired stop position.

LOADED DOWN SPEED CONTROL, STRUCTURE AND OPERATION For down speedcontrol of a loaded elevator there is supplied. a poppet valve indicatedgenerally by the reference character 200 in communication with the firstcombination cavity 73 through hydraulicline 126 and in furthercommunication with the second combination cavity 74 through a passage201.

As shown in FIG. 8 the poppet valve 200 has at one end a frusto-conicalsurface 202 joining a reduced portion 203, the reduced portionterminating in a hemispherical surface 204. At the other end, axiallyconcentric with the frusto-conical surface 202 and reduced portion 203is another reduced portion 205. The reduced portion 205 is surroundedfor a portion of its length by a spring 206 which abuts interiorlyagainst a surface 207 formed in a plug 208 engaged threadedly into apoppet valve body 209. In the body 209 is a chamber 210 and the chamber210 in cooperation with the reduced portion 203 forms an annular orificeterminating at one end in a seat 213 and at the other end in a chamber214.

The plug 208 has an axially concentric opening 215 in its lower endthrough which the reduced portion 205 of the poppet 200 passes in guidedrelationship.

The annular chamber 210 communicates with the dump line 17, previouslyreferred to, through the passage 201. More particularly the line ofcommunication is through a chamber 216 in the poppet valve body 209,which surrounds the poppet valve, thence through what may be termed achamber 217 to the opening 215 in the plug 208 and from there to thepassage 201.

The hydraulic line 216 communicates with the annular chamber 210 throughan annular recess 212 and a radial passage 211, both formed in andthrough poppet valve body 209. The hemispherical surface 204 intimatelyengages a recess 218 in a stem 219 through the action of the spring 206urging the poppet 200 upwards. A spring 220 urges an upper diaphragmplate 221 downward, the diaphragm plate 221 being held compressivelyagainst a diaphragm 222 and a lower diaphragm plate 224 by a nut 223threadedly engaging the stem 219. The lower diaphragm plate 224 isfurther restrained by a shoulder 225 on the stem 219. The diaphragm 222is circumferentially enclosed and sealed between a body adaptor 226 andan upper regulator housing 227 by means of suitable fasteners not shown.Positioned as described the diaphragm establishes a relatively closeddiaphragm cavity 236 and a relatively open diaphragm cavity 237. Thecavity 237 communicates through a hydraulic line 238 with the secondcombination cavity 74. The lower end of the spring 220 abuts the upperdiaphragm plate 221 and is restrained at its upper end by a springretainer cap 228. The cap 228 is threadedly engaged at one end to theupper regulator housing 227 and at the other end to an up levelingadjustor not 229, the adjustor nut having an axial bore 230 throughwhich stem 219 slides in close proximity. By the structure justdescribed axial concentricity is assured. The stem 219 terminates at itsupper end in a 106012 mus thread 231 on which is a transition nut 232.The up leveling adjustor nut 229 is in a position of engagement with abeveled spring washer assembly 233. Since the spring 220 is strongerthan the spring 206, the stem 219 is urged downwardly until the nut 232is moved against the nut 229.

- Proper positioning of the nuts 232 and 229 will result in a degree ofopening between seat 213 and the frustoconical surface 202 such that thearea formed is larger than that of slot 94 in the down closing and stopvalve assembly 90 (see FlG. 2) such that when the main down solenoid 92is energized, and the down pilot valve 131 is moved from normally closedto open position and the pressure in first combination cavity 73 (see Fl6. 3) will fall to a figure substantially below that in the passage 79.The combination valve element 71 will move downwardly as previouslydetailedin the paragraph treating with down travel, but now, as thefluid in the second combination cavity 74 passes through the area of thehydraulic line 238, fluid pressure which was at atmospheric is nowmodified slightly by the positioning of a butterfly vane 240 such thatthis pressure acting upon the area of the diaphragm 222 displaces theupper diaphragm plate 221 upwards against the in sistence of spring 220,carrying with it the stem 219, thereby releasing the poppet valve 200 tomove upwards under the urging of the spring 206. The upward movementbrings the frusto-conical surface 202 into intimate contact with theseat 213 which contact effectively closes off hydraulic line 126,thereby trapping fluid in first combination cavity 73 previously atatmospheric pressure, modified slightly, such that pressure fromhydraulic line 14 passing through down closing and stop valve assembly90 serves to increase pressure in the first combination cavity 73. Thispressure assisted by spring 83 serves to move the combination valveelement 71 upwardly thereby to partially close the opening between thepilot operated combination valve element 71 and the combination valveseat 72 until the flow of fluid through second combination cavity 74 isdecreased and a balance of forces exists between fluid pressure incavity 237 acting upon diaphragm 222 and spring 220 in conjunction withbevelled spring washer assembly 233, thereby effectively limiting therate" of fluid flow through second combination cavity 74 which in turnlimits the downward speed of the elevator 1 1.

Reference is made at this time to US. Pat. No. 3,474,231 1 issued Oct.28, 1969 citing temperature compensation applicable to this control.

While the invention has herein been shown and described in what isconceived to be a practical and effective embodiment, it is recognizedthat departures may be made therefrom with the scope of the invention,which is not to be limited to the details disclosed herein but is to beaccorded the full scope of the claims so as to embrace any and allequivalent devices.

Having described the invention, what is claimed as new in support ofLetters Patent is:

1. A unit valve assembly for operation of a hydraulic elevator ramcomprising a housing having a plurality of valve chambers, a bypassvalve element in one of said chambers separating said chamber into firstand second bypass cavities, an up level valve element separating anotherof said chambers into first and second up level cavities and acombination down level and down main valve element separating stillanother of said chambers into first and second combination cavities,communicating passages in said housing between said chambers, andadjusting means for said respective valve elements located all on oneside of said housing.

2. A unit valve as in claim 1 wherein the valve chambers are elongatedand with axes of the chambers in parallel relationship and the up levelvalve element has an open operative conditionestablishing'commu-nication between the cavities of the respectivechamber.

3. A unit valve as in claim. 1 wherein the up level valve has an openoperative condition establishing communication between the cavities ofthe respective chamber and the combination valve element has an openoperative condition establishing communication between one of thecavities of the respective chamber and said ram.

4. A unit valve as in claim 1 wherein the adjusting means for said uplevel valve element includes a progressively variable orifice means.comprising two mutually adjustable elements adapted to be set atselective positions relative to each other whereby to selectively varythe rate of deceleration of said ram.

5. A unit valve assembly for operation of a hydraulic elevator ramcomprising a housing having a plurality of valve chambers therein, abypass valve having a bypass valve element in one of said chambers, anup level valve having an up level valve element in another of saidchambers and a combination down level and down main valve having acombination valve element in still another of said chambers, a supply offluid under pressure to said up level valve and anup level controlassembly in operating engagement with said up level valve, a pluralityof electrically initiated hydraulic control valves in operatingrelationship with said ram, said control valves being respectively forup level acceleration, up transition, up dump, down acceleration, anddown stop, a hydraulic circuit interconnecting said hydraulic controlvalves, said down level hydraulic control assembly and said up levelcontrol assembly, said hydraulic control valves and assemblies havingadjusting elements responsive to manual adjustment, manual adjustingelements respectively for said bypass valve element and said combinationvalve element, a majority of said adjusting elements being located onand accessible from one side of said housing.

6. A unit valve assembly as in claim 5 wherein said control valves andsaid control assemblies have longitudinal axes in parallel relationshipin said housing.

7. A unit valve assembly for operation of a hydraulic elevator ramcomprising a housing having a plurality of valve chambers therein, abypass valve having a bypass valve element intermediate opposite bypasscavities in one of said chambers, an up level valve having an up levelvalve element intermediate opposite up level cavities in another of saidchambers and a combination down level and down main valve having acombination valve element intermediate opposite combination cavities instill another of said chambers, a bypass outlet from one of said bypasscavities, a supply of fluid under pressure to one of said up levelcavities and a passage in said housing in communication between saidlast two cavities and subject to control by said bypass valve, an uplevel control assembly in operating engagement with said up level valveelement and in communication respectively with said one up level cavityand the other bypass cavity, one of said combination cavities being incommunication with said bypass outlet, a down level hydraulic controlassembly in communication with the other of said combination cavities, aplurality of electrically initiated hydraulic control valves inoperating relationship with said ram, said control valves beingrespectively for up acceleration, up transition, up dump, downacceleration and down stop, a hydraulic circuit interconnecting saidhydraulic control valves, said down level hydraulic control assembly andsaid up level control assembly, said hydraulic control valves andassemblies having adjusting elements responsive to manual adjustment,manual adjusting elements respectively for said by pass valve elementand said combination valve element, most of said adjusting elementsbeing located on and accessible from one side of said housing a 8. Aunit valve assembly for operation of a hydraulic elevator ram comprisinga housing having a plurality of valve chambers therein, a bypass valvehaving a bypass valve element intermediate opposite bypass cavities inone of said chambers, an up level valve having an up level valve elementintermediate opposite up level cavities in another of said chambers anda combination down level and down main valve having a combination valveelement intermediate opposite combination cavities in still another ofsaid chambers, a bypass outlet from one of said bypass cavities, asupply of fluid under pressure to one of said up level cavities and apassage in said housing in communication between said last two cavitiesand subject to control by said bypass valve, an up level controlassembly in operating engagement with said up level valve element and incommunication respectively with said one up level cavity and the otherbypass cavity, a valve seat in cooperation with said up level valve.element adapted when open to interconnect said up level cavities, avalve seat in cooperation with said combination valve element adaptedwhen open to interconnect the other of said bypass cavities and saidram, one of said combination cavities being in communication with saidbypass outlet, a down level hydraulic control assembly in communicationwith the other of said combination cavities, a plurality of electricallyinitiated hydraulic control valves in operating relationship with saidram, said control valves being respectively for up acceleration, uptransition, up dump, down acceleration and down stop, a hydrauliccircuit interconnecting said hydraulic control valves, said down levelhydraulic control assembly and said up level control assembly, saidhydraulic control valves and assemblies having adjusting elementsresponsive to manual adjustment, manual adjusting elements respectivelyfor said bypass valve elements and said combination valve element, allof said adjusting elements being located on and accessible from one sideof said housing.

9. A unit valve for control of a hydraulic elevator comprising an uptransition valve assembly, a housing having an up level chamber and abypass chamber therein, an up level valve element in said chamberseparating said chamber into a first up level cavity and a second uplevel cavity, and a valve seat between said cavities in operatingrelationship with said up level valve element, a bypass valve elementseparating said bypass chamber into a first bypass cavity and a secondbypass cavity, a supply means for hydraulic fluid under pressure to saidfirst up level cavity, a bypass passage from said first up level cavityto said first bypass cavity and a passage from said second up levelcavity to pass fluid to said elevator, an up level valve assemblycomprising a tubular jacket in said housing in axial alignment with saidup level valve element, a spoolslidably mounted in said jacket andsecuredto said up level valve element, said spool having a boretherethrough communicating between said first up level cavity and theinterior of said tubular jacket, an annular hollow neck within saidtubular jacket and surrounding a portion of said spool, means forming anexterior annular space around said neck and a passage between said spaceand said second bypass cavity, a port through the wall of said neckcommunicating between said space and the interior of said tubularjacket, a reduced portion of said spool including a progressivelyvariable port restricting portion, said reduced portion being movablewith said spool in response to movement of said up level valve elementto present different portions thereof to said port whereby to vary thecapacity of said port to pass hydraulic fluid, and a hydraulic linecommunicating between said exterior annular space and said up transitionvalve assembly.

10. In a hydraulic elevator control system including a pump, a ram, areservoir and valves for upward and downward control of said ram, thecombination of an up level valve assembly comprising a housing having achamber and an up level valve element on a valve seat separating saidchamber into first and second up level cavities, said valve assemblycomprising a casing having a space therein opposite portions of whichare in communication respectively with a bypass valve assembly and an uptransition valve assembly, one portion of said space being an interiorspace and another portion of said space being an exterior space, a portinterconnecting said interior and exterior spaces, and a spool having apart thereof of progressively varying configuration adjacent said port,and means .for shifting said part whereby to varythe passages of fluidbetween said interior and exterior spaces.

1 1. A system as in claim 10 wherein said interior and exterior spacesare concentric annular spaces.

12. A system as in claim 10 wherein an end of said spool has a slidingsealed fit in said interior space and forms a cavity, and a bore throughsaid spool in communication respectively with said cavity and one ofsaid up level cavities.

13. A system as in claim 12 wherein said spool is mounted on and carriedby said up level valve element.

14. A unit valve assembly for operation of a hydraulic elevator ramcomprising a housing having a plurality of valve chambers therein, abypass valve having a bypass valve element intermediate opposite bypasscavities in one of said chambers, an up level valve having an up levelvalve element intermediate opposite up level cavities in another of saidchambers, and a combination down level and down main valve having acombination valve element intermediate opposite combination cavities instill another of said chambers, a bypass outlet from one of said bypasscavities, a supply of fluid under pressure to one of said up levelcavities, and a passage in said housing in communication between saidlast two cavities and subject to control by said bypass valve, a downclose and stop valve assembly in communication with said ram and withsaid down level and main valve assembly, and an electrically initiatedhydraulic control valve for down acceleration, said hydraulic controlvalve for down acceleration and said down close and stop valve assemblyeach having a variable orifice therein and manual adjusting means forsaid orifice, whereby to control full down speed operation of said ram.

15. A systemas in claim 14 including a reservoir for fluid from saidvalve assembly, a hydraulic discharge line between said hydraulic valvefor down acceleration and said reservoir, an auxiliary hydraulic linefrom one of said combination cavities on an outflow side of saidcombination down level and down main valve, and a poppet valve in thehydraulic discharge line, said poppet valve being in communication withsaid auxiliary line, whereby to limit down speed of said ram by controlof flow through said discharge line.

16. A system as in claim. 15 including a manual con trol on said poppetvalve whereby to set the limit of operation of said poppet valve and thetop down speed of said ram.

17. A valve assembly for operation of a hydraulic elevator ramcomprising a housing having a plurality of valve chambers therein, acombination down level and down main valve having a combination valveelement intermediate opposite combination cavities in one of saidchambers, a down close and stop valve assembly in communication withsaid ram and with said down level and main valve assembly, and anelectrically initiated hydraulic control valve in communication with theoutlet side of said down close and stop valve assembly for downacceleration, said hydraulic control valve for down acceleration andsaid down close and stop valve assembly each having a variable orificetherein, whereby to control full down speed operation of said ram, and aloaded down speed control poppet valve assembly having one line ofcommunication with the outlet side of said hydraulic control valve andhaving another line of communication with the outlet side of saidcombination down level and down main valve,

' outlet side of said hydraulic control valve and the other of saidchambers being in communication with the outlet side of said combinationdown level and down main valve.

19. A valve as in claim 18 wherein there are resilient meansrespectively of greater and lesser bias operatively associated-with saidstern on opposite sides of said poppet valve and acting in oppositedirections whereby to normally bias the poppet valve toward openposition.

20. A valve as in claim 19 wherein there is a diaphragm on the stem, adiaphragm chamber surrounding said diaphragm and separated by saiddiaphragm into a closed diaphragm cavity and an open diaphragm cavity,the resilient means of greater bias being in the closed diaphragmcavity, said open dlap ragm cavity being in communication with theoutlet side of said down level and down main valve.

21. in a valve assembly for operation of a hydraulic elevator ramcomprising a housing having a plurality of valve chambers, a bypassvalve element in one of said chambers separating said chamber into firstand second bypass cavities, an up level valve element separating anotherof said chambers into first and second up level cavities, and acombination down level and down main valve element separating stillanother of said chambers into first and second combination cavities,communicating means in said housing between said chambers, a poppetvalve assembly having a valve element therein located on said housing,and a control valve for down acceleration on said housing, oppositesides of said poppet valve being in communication respectively with theoutlet side of the control valve for down acceleration and the outletside of the combination down level and down main valve element, andadjusting means for a majority of said valve elements located onsubstantially one side of said housing.

an on

1. A unit valve assembly for operation of a hydraulic elevator ramcomprising a housing having a plurality of valve chambers, a bypassvalve element in one of said chambers separating said chamber into firstand second bypass cavities, an up level valve element separating anotherof said chambers into first and second up level cavities and acombination down level and down main valve element separating stillanother of said chambers into first and second combination cavities,communicating passages in said housing between said chambers, andadjusting means for said respective valve elements located all on oneside of said housing.
 2. A unit valve as in claim 1 wherein the valvechambers are elongated and with axes of the chambers in parallelrelationship and the up level valve element has an open operativecondition establishing communication between the cavities of therespective chamber.
 3. A unit valve as in claim 1 wherein the up levelvalve has an open operative condition establishing communication betweenthe cavities of the respective chamber and the combination valve elementhas an open operative condition establishing communication between oneof the cavities of the respective chamber and said ram.
 4. A unit valveas in claim 1 wherein the adjusting means for said up level valveelement includes a progressively variable orifice means comprising twomutually adjustable elements adapted to be set at selective positionsrelative to each other whereby to selectively vary the rate ofdeceleration of said ram.
 5. A unit valve assembly for operation of ahydraulic elevator ram comprising a housing having a plurality of valvechambers therein, a bypass valve having a bypass valve element in one ofsaid chambers, an up level valve having an up level valve element inanother of said chambers and a combination down level and down mainvalve having a combination valve element in still another of saidchambers, a supply of fluid under pressure to said up level valve and anup level control assembly in operating engagement with said up levelvalve, a plurality of electrically initiated hydraulic control valves inoperating relationship with said ram, said control valveS beingrespectively for up level acceleration, up transition, up dump, downacceleration, and down stop, a hydraulic circuit interconnecting saidhydraulic control valves, said down level hydraulic control assembly andsaid up level control assembly, said hydraulic control valves andassemblies having adjusting elements responsive to manual adjustment,manual adjusting elements respectively for said bypass valve element andsaid combination valve element, a majority of said adjusting elementsbeing located on and accessible from one side of said housing.
 6. A unitvalve assembly as in claim 5 wherein said control valves and saidcontrol assemblies have longitudinal axes in parallel relationship insaid housing.
 7. A unit valve assembly for operation of a hydraulicelevator ram comprising a housing having a plurality of valve chamberstherein, a bypass valve having a bypass valve element intermediateopposite bypass cavities in one of said chambers, an up level valvehaving an up level valve element intermediate opposite up level cavitiesin another of said chambers and a combination down level and down mainvalve having a combination valve element intermediate oppositecombination cavities in still another of said chambers, a bypass outletfrom one of said bypass cavities, a supply of fluid under pressure toone of said up level cavities and a passage in said housing incommunication between said last two cavities and subject to control bysaid bypass valve, an up level control assembly in operating engagementwith said up level valve element and in communication respectively withsaid one up level cavity and the other bypass cavity, one of saidcombination cavities being in communication with said bypass outlet, adown level hydraulic control assembly in communication with the other ofsaid combination cavities, a plurality of electrically initiatedhydraulic control valves in operating relationship with said ram, saidcontrol valves being respectively for up acceleration, up transition, updump, down acceleration and down stop, a hydraulic circuitinterconnecting said hydraulic control valves, said down level hydrauliccontrol assembly and said up level control assembly, said hydrauliccontrol valves and assemblies having adjusting elements responsive tomanual adjustment, manual adjusting elements respectively for said bypass valve element and said combination valve element, most of saidadjusting elements being located on and accessible from one side of saidhousing.
 8. A unit valve assembly for operation of a hydraulic elevatorram comprising a housing having a plurality of valve chambers therein, abypass valve having a bypass valve element intermediate opposite bypasscavities in one of said chambers, an up level valve having an up levelvalve element intermediate opposite up level cavities in another of saidchambers and a combination down level and down main valve having acombination valve element intermediate opposite combination cavities instill another of said chambers, a bypass outlet from one of said bypasscavities, a supply of fluid under pressure to one of said up levelcavities and a passage in said housing in communication between saidlast two cavities and subject to control by said bypass valve, an uplevel control assembly in operating engagement with said up level valveelement and in communication respectively with said one up level cavityand the other bypass cavity, a valve seat in cooperation with said uplevel valve element adapted when open to interconnect said up levelcavities, a valve seat in cooperation with said combination valveelement adapted when open to interconnect the other of said bypasscavities and said ram, one of said combination cavities being incommunication with said bypass outlet, a down level hydraulic controlassembly in communication with the other of said combination cavities, aplurality of electrically initiated hydraulic control valves inoperating relationship with said ram, said control valves beingrespectiveLy for up acceleration, up transition, up dump, downacceleration and down stop, a hydraulic circuit interconnecting saidhydraulic control valves, said down level hydraulic control assembly andsaid up level control assembly, said hydraulic control valves andassemblies having adjusting elements responsive to manual adjustment,manual adjusting elements respectively for said bypass valve elementsand said combination valve element, all of said adjusting elements beinglocated on and accessible from one side of said housing.
 9. A unit valvefor control of a hydraulic elevator comprising an up transition valveassembly, a housing having an up level chamber and a bypass chambertherein, an up level valve element in said chamber separating saidchamber into a first up level cavity and a second up level cavity, and avalve seat between said cavities in operating relationship with said uplevel valve element, a bypass valve element separating said bypasschamber into a first bypass cavity and a second bypass cavity, a supplymeans for hydraulic fluid under pressure to said first up level cavity,a bypass passage from said first up level cavity to said first bypasscavity and a passage from said second up level cavity to pass fluid tosaid elevator, an up level valve assembly comprising a tubular jacket insaid housing in axial alignment with said up level valve element, aspool slidably mounted in said jacket and secured to said up level valveelement, said spool having a bore therethrough communicating betweensaid first up level cavity and the interior of said tubular jacket, anannular hollow neck within said tubular jacket and surrounding a portionof said spool, means forming an exterior annular space around said neckand a passage between said space and said second bypass cavity, a portthrough the wall of said neck communicating between said space and theinterior of said tubular jacket, a reduced portion of said spoolincluding a progressively variable port restricting portion, saidreduced portion being movable with said spool in response to movement ofsaid up level valve element to present different portions thereof tosaid port whereby to vary the capacity of said port to pass hydraulicfluid, and a hydraulic line communicating between said exterior annularspace and said up transition valve assembly.
 10. In a hydraulic elevatorcontrol system including a pump, a ram, a reservoir and valves forupward and downward control of said ram, the combination of an up levelvalve assembly comprising a housing having a chamber and an up levelvalve element on a valve seat separating said chamber into first andsecond up level cavities, said valve assembly comprising a casing havinga space therein opposite portions of which are in communicationrespectively with a bypass valve assembly and an up transition valveassembly, one portion of said space being an interior space and anotherportion of said space being an exterior space, a port interconnectingsaid interior and exterior spaces, and a spool having a part thereof ofprogressively varying configuration adjacent said port, and means forshifting said part whereby to vary the passages of fluid between saidinterior and exterior spaces.
 11. A system as in claim 10 wherein saidinterior and exterior spaces are concentric annular spaces.
 12. A systemas in claim 10 wherein an end of said spool has a sliding sealed fit insaid interior space and forms a cavity, and a bore through said spool incommunication respectively with said cavity and one of said up levelcavities.
 13. A system as in claim 12 wherein said spool is mounted onand carried by said up level valve element.
 14. A unit valve assemblyfor operation of a hydraulic elevator ram comprising a housing having aplurality of valve chambers therein, a bypass valve having a bypassvalve element intermediate opposite bypass cavities in one of saidchambers, an up level valve having an up level valve elementintermediate opposite up level cavities in another of said chambers, anda combination down level and down main valve having a combination valveelement intermediate opposite combination cavities in still another ofsaid chambers, a bypass outlet from one of said bypass cavities, asupply of fluid under pressure to one of said up level cavities, and apassage in said housing in communication between said last two cavitiesand subject to control by said bypass valve, a down close and stop valveassembly in communication with said ram and with said down level andmain valve assembly, and an electrically initiated hydraulic controlvalve for down acceleration, said hydraulic control valve for downacceleration and said down close and stop valve assembly each having avariable orifice therein and manual adjusting means for said orifice,whereby to control full down speed operation of said ram.
 15. A systemas in claim 14 including a reservoir for fluid from said valve assembly,a hydraulic discharge line between said hydraulic valve for downacceleration and said reservoir, an auxiliary hydraulic line from one ofsaid combination cavities on an outflow side of said combination downlevel and down main valve, and a poppet valve in the hydraulic dischargeline, said poppet valve being in communication with said auxiliary line,whereby to limit down speed of said ram by control of flow through saiddischarge line.
 16. A system as in claim 15 including a manual controlon said poppet valve whereby to set the limit of operation of saidpoppet valve and the top down speed of said ram.
 17. A valve assemblyfor operation of a hydraulic elevator ram comprising a housing having aplurality of valve chambers therein, a combination down level and downmain valve having a combination valve element intermediate oppositecombination cavities in one of said chambers, a down close and stopvalve assembly in communication with said ram and with said down leveland main valve assembly, and an electrically initiated hydraulic controlvalve in communication with the outlet side of said down close and stopvalve assembly for down acceleration, said hydraulic control valve fordown acceleration and said down close and stop valve assembly eachhaving a variable orifice therein, whereby to control full down speedoperation of said ram, and a loaded down speed control poppet valveassembly having one line of communication with the outlet side of saidhydraulic control valve and having another line of communication withthe outlet side of said combination down level and down main valve,whereby to modify the full down speed operation of said ram under load.18. A valve as in claim 17 wherein there is a valve stem for the poppetvalve and a valve element and valve seat operatively associated withsaid stem, chambers in said valve on opposite sides of said valve seat,one of said chambers being in communication with the outlet side of saidhydraulic control valve and the other of said chambers being incommunication with the outlet side of said combination down level anddown main valve.
 19. A valve as in claim 18 wherein there are resilientmeans respectively of greater and lesser bias operatively associatedwith said stem on opposite sides of said poppet valve and acting inopposite directions whereby to normally bias the poppet valve towardopen position.
 20. A valve as in claim 19 wherein there is a diaphragmon the stem, a diaphragm chamber surrounding said diaphragm andseparated by said diaphragm into a closed diaphragm cavity and an opendiaphragm cavity, the resilient means of greater bias being in theclosed diaphragm cavity, said open diaphragm cavity being incommunication with the outlet side of said down level and down mainvalve.
 21. In a valve assembly for operation of a hydraulic elevator ramcomprising a housing having a plurality of valve chambers, a bypassvalve element in one of said chambers separating said chamber into firstand second bypass cavities, an up level valve element separating anotherof said Chambers into first and second up level cavities, and acombination down level and down main valve element separating stillanother of said chambers into first and second combination cavities,communicating means in said housing between said chambers, a poppetvalve assembly having a valve element therein located on said housing,and a control valve for down acceleration on said housing, oppositesides of said poppet valve being in communication respectively with theoutlet side of the control valve for down acceleration and the outletside of the combination down level and down main valve element, andadjusting means for a majority of said valve elements located onsubstantially one side of said housing.